RE: About SQUID and SNMP TRAPS , and snmp in general

On Mon, 11 Jul 2005, Lombao, Cesar wrote:

> I was taking a look on the source code, and, besides the functions
> provided by the UCM snmp library, I don't see any other code to send
> traps.

There was quite a bit of code deleted from the library some years back..
have a quite strong memory of a fair bit of this being related to traps
and set PDUs.

> In fact, I'm still trying to understand how this library and the
> snmp_core.cc and snmp_agent.cc modules work together.

the library is used for encoding/decoding. snmp_agent.cc defines the
general MIB extractors and snmp_core.c is the agent implementation (and
also defines the MIB for some reason.. but this part is better moved to
snmp_agent.cc)

The original agent in the CMU SNMP library is not used for mainly the same
reason the agent in net-snmp doesn't fit well within Squid I suppose.

> To send a trap is something, in theory, trivial. Open a dgram socket,
> and send the info to the trapsink.

Yes, and is why I think currently is easier to just resurrect/reimplement
the SNMP PDU processing components for this rather than to look into how
to fit a more modern SNMP agent into Squid.

> The point is not that, the point is all the details surronding that:
> MIB:
> Needs to be defined in the MIB the traps sent.
>
> TRAPS:
> Needs to be defined wich traps be sent. (When special errors happen?
> when MIB updated?)

Yes.

The two go pretty much together. When to send traps and what to include.

> CONFIGURATION:
> If SQUID uses its own snmp agent, then is needed to add a confguation
> line to set the trapsink destianation for the traps sent.

Yes.

> And of course, all the time I was talking about SNMPv1 only ;-)

Only desire to support SNMPv1/2c at this time. For SNMPv3 we better look
at using a modern agent.

Another point to consider is if ther is events requiring an SNMP Inform
message for somewhat reliable delivery, or if best effort traps is
sufficient.

Regards
Henrik
Received on Mon Jul 11 2005 - 08:37:45 MDT